Article and method of forming a support structure

ABSTRACT

The article used and the method of forming a support structure, such as an orthopedic cast, comprising interlacing one or more flexible, pliable filaments having a photopolymerizable material enclosed entirely within the interior of the filaments so as to form a pliable fabric article which can be readily conformed to the surface with which it is in contact and exposing the fabric article to a source of wave energy, such as ultra-violet light, which effects polymerization of the material within the filament and transforming the fabric into a rigid structure entirely by means of the mechanical interlock formed between the filaments; thereby forming a rigid support structure without the application of a malodorous, sticky or powdered stiffening or bonding agent to the outer surface of the filaments or fabric.

The present invention relates generally to an improved method and meansfor maintaining an element or structure rigid, and more particularly toa novel method and means for providing an improved rigid supportingstructure, such as an orthopedic cast, which can be conveniently usedwhere conditions require that the supporting structure be pliable duringinstallation and rigid during use.

It has heretofore been found advantageous to use plastic materials formaking supporting structures, such as orthopedic casts, because theplastic materials are lighter, more easily applied and more resistant towater than conventional plaster casts. One method of making plasticorthopedic casts is described in U.S. Pat. No. 3,421,501, wherein awoven or non-woven fabric has on the surface of the fibers forming thefabric and in the space between the fibers an ultra-violet curablepolymer, such as a polymerizable organic composition containing aphotosensitizing polymerization initiator which is activated by exposureto ultra-violet light, and after wrapping the fabric about a patient'sfractured limb, the impregnated fabric is exposed to ultra-violet lightto effect polymerization of the organic material and formation of arigid light weight plastic cast. Other materials and methods forimpregnating a fabric and forming a plastic orthopedic cast aredescribed in U.S. Pat. Nos. 3,618,599, 3,613,675 and 2,812,570.

Plastic orthopedic casts formed in situ in accordance with the foregoingdisclosures have many advantages over a conventional plaster cast.However, forming orthopedic plastic casts from fabrics which have theinterstices thereof impregnated with a plastic material in accordancewith the prior art has many objectionable features. For example, theseprior art impregnated fabrics either have an objectionable odor, aretacky during application, or require the use of hand cream or jelly tofacilitate proper smoothing and blending of the layers of impregnatedfabric. And, it is desirable to use rubber gloves when forming anorthopedic cast from such impregnated fabrics. It is also possible forthe impregnating plastic material to come into direct contact with thebody of the patient or the attendant, causing irritation or otherdeleterious effects unless special precautions are taken to maintain theimpregnated fabric out of contact with the exposed body surfaces. And,the polymerizable material which is impregnated in the interstices ofthe fabric may deteriorate or stiffen during storage, if exposed to thesurrounding atmosphere unless special precautions and packagingprocedures are maintained. Fabrics which are impregnated with thepolymerizable material are limited in the amount of handling and moldingwhich can be applied thereto during storage and application. Also, theamount of air circulation or breathing of prior art plastic casts islimited, because a significant proportion of the openings in the fabricare permanently blocked or reduced in size by the impregnatedpolymerizable plastic material.

Accordingly, it is an object of the present invention to provide amethod and means for providing an improved flexible, pliable or elasticelement which is adapted to be readily manipulated and shaped into adesired configuration and thereafter made rigid by exposing to a sourceof wave energy so as to maintain the desired configuration.

It is a further object of the present invention to provide an improvedmethod and means for shaping an article into a desired configuration andthereafter immobilizing the article without impregnating the surface ofthe article with a stiffening agent which is sticky or malodorous.

It is still another object of the present invention to provide animproved pliable or flexible fabric which can be immobilized on exposureto wave energy without having the fabric impregnated with a stiffeningagent such that the fibers forming the fabric have the stiffening agentin surrounding relationship therewith.

It is a still further object of the present invention to provide animproved spun plastic flexible, pliable or elastic filament or tubulewhich is adapted to be immobilized on exposure to a suitable source ofwave energy without having a stiffening agent exposed on the surface ofthe filament or tubule.

It is still another object of the present invention to provide animproved method and means for forming in situ an orthopedic cast orsupport member which can be immobilized on exposure to wave energy.

It is still further an object of the present invention to provide animproved plastic orthopedic cast or like body support device whichpermits improved air circulation and breathing of the cast.

Other objects of the present invention will be apparent to one skilledin the art from the detailed description and claims to follow when readin conjunction with the accompanying drawing, wherein:

FIG. 1 is an enlarged cross-sectional view of an elongated flexible,pliable or elastic element embodying the present invention;

FIG. 2 is an enlarged cross-sectional view of the element of FIG. 1 in arigid immobilized form;

FIG. 3 is a cross-sectional view of a modified form of an elongatedflexible, pliable or elastic element embodying the present invention;

FIG. 4 is a cross-sectional view of a still further modified form of anelongated flexible, pliable or elastic element embodying the presentinvention;

FIG. 5 is a diagrammatic perspective view of a further embodiment of thepresent invention comprising a pliable cylindrical fabric sleeve-likearticle formed from the element of FIG. 1;

FIG. 6 is a diagrammatic perspective view of the article of FIG. 5applied to the wrist of a patient as an orthopedic cast; and

FIG. 7 is a diagrammatic perspective view of a still further embodimentof the present invention showing a stockinette formed of the element ofFIG. 1 applied to the foot and ankle of a patient.

The objects of the present invention are achieved by providing anelongated flexible, pliable or elastic element, such as a small diameterfilament or tubule, which is comprised of a filament forming material,preferably of a high molecular weight organic composition, havingenclosed entirely within the main body portion thereof and extendingthroughout the length thereof a polymerizable material which remains ina pliable or liquid state until exposed to ultra-violet light or otherforms of radiant or wave energy and which is capable of beingpolymerized into a rigid form on exposure to ultra-violet light or otherform of radiant or wave energy having a sufficient intensity to effectpolymerization and thereby rigidifying the filament or tubule and anyarticle or structure of which the filament is a part. More particularly,the elongated flexible, pliable or elastic element embodying the presentinvention preferably comprises an elongated small diameter spun filamentwhich has a polymerizable organic material containing where required asensitizing polymerization initiator protectively enclosed and retainedentirely within the body of the spun filament. The polymerizable organicmaterial can be enclosed within one or more longitudinally extendingpassages or spaced pockets formed in the spun filament. Thus, thefiber-like article can be a spun tube-like element having an axialpassage extending longitudinally therethrough with the polymerizableorganic material enclosed within the axial passage, or the elongatedelement can have a plurality of uniformly spaced longitudinallyextending passages or pockets formed within a flexible, pliable orelastic small diameter rod-like body portion of the element with thepolymerizable organic material protectively enclosed therein. Thepolymerizable organic material and the polymerization initiator can alsobe enclosed within a plurality of elongated randomly spaced passages orpockets formed within a spun tubular or rod-like member with the pocketsbeing relatively short and distributed throughout the spun pliableplastic in overlapping spaced relationship within the wall of a tubularmember or throughout the body of a rod-like member. The elongatedflexible, pliable or elastic element or an article formed therefrom,after being shaped to the desired configuration, can be readilytransformed into a rigid form by exposing the element or article to asuitable source of wave energy, preferably a source of ultra-violetlight which effects polymerization.

In one preferred embodiment of the present invention as shown in FIGS. 1and 2, a high molecular weight organic composition is extruded through acomposite spinning head (not shown) to form a flexible, pliable orelastic small diameter filament or tubule 10 comprised of a flexible,pliable or elastic cylindrical outer sheath or wall section 11 and alumen or core portion 12 which is filled with a pliable or liquidpolymerizable organic material 13 having where required aphotosensitizing polymerization initiator mixed therewith which isadapted to be transformed by polymerization into a rigid core 14 (seeFIG. 2) when the filament is exposed to an appropriate source ofultra-violet light. The filament and tubules which can be used in thepresent invention preferably have a diameter ranging between about 0.001inches and 0.200 inches. Spinning nozzles suitable for making flexible,pliable or elastic filaments having the foregoing structures are wellknown in the textile fiber spinning art, and one such multiple-holespinning nozzle is shown in U.S. Pat. No. 3,075,241. A spinneret forforming fibers having a centered core is also shown in U.S. Pat. No.3,458,615.

While the foregoing fiber-like filaments or tubules are capable of beingused directly as packaging material for immobilizing the contents of acontainer during transport by exposing the tubules to ultra-violet lightafter the filaments or tubules supportively contact an article withinthe container, a particularly useful application of the foregoingfilaments or tubules comprises interlacing one or more of the flexible,pliable or elastic filaments or tubules, as by knitting, weaving orfelting, to provide a fabric in the form of an elongated strip, sleeve,stockinette, glove, body stocking or like stretchable and form-fittingarticle of wearing apparel. The article formed preferably has aconsiderable degree of elasticity which can be obtained from the type ofthe interlacing used to form the fabric or the elastic properties of thespun fibers themselves, so that the article when applied to the bodymember or other structure will conform generally to the contours thereofand, after being transformed into its substantially rigid form, willprovide a light weight, water proof, attractive orthopedic cast, braceor splint which will effectively immobilize a body fracture or providethe desired support for a structure in contact therewith.

FIG. 3 shows a modified form of the invention in which the flexible,pliable or elastic small diameter filament 15 has an extruded rod-likebody section 16 with a plurality of uniformly spaced longitudinallyextending passages or pockets 17 which are filled with a liquid orpliable polymerizable organic material 18.

FIG. 4 shows a further modified form of the invention in which theflexible, pliable or elastic small diameter filament 20 has an extrudedrod-like body section 21 with a plurality of randomly spaced passages orpockets 22 enclosed within the body section 21 and filled with a liquidor pliable polymerizable organic material 23 which is readilypolymerizable to a rigid solid on exposure to a source of wave energy,such as ultra-violet light.

FIGS. 5 and 6 of the drawing illustrate an embodiment of the presentinvention wherein a cylindrical fabric sleeve 30 is formed so as to haveelastic properties by interlacing, preferably by knitting, a pluralityof the flexible, pliable or elastic tubular elements 10 of FIG. 1 beforeexposing the elements 10 to ultra-violet light. The elastic propertiesare provided by the type of the interlacing used in forming the sleeve30 or the elastic properties of the tubular element per se. In use thesleeve 30 can be placed over a patient's hand and wrist 31 so that itconforms generally to the shape of the hand and wrist (see FIG. 6). Whenthe sleeve 30 is exposed to ultra-violet light, the liquid or pliablecore material 13 within the tubular elements 10 is transformed into arigid core 14 as a result of the polymerization reaction initiated byexposing the sleeve 30 to the ultra-violet light. The tubular elements10 after polymerization is complete are mechanically interlocked to forma rigid, lightweight, waterproof cast on the patient's wrist and hand.

FIG. 7 illustrates a sock-like article 35 formed by interlacing,preferably by knitting, the flexible, pliable or elastic tubular element10 of FIG. 1. The stockinette, being resilient prior to exposure toultra-violet light, is readily placed over a patient's ankle and foot36. When exposed to ultra-violet light the liquid or pliable corematerial 13 within the tubular elements 10 is polymerized into a rigidform causing the tubular elements to mechanically interlock andproviding a rigid, lightweight, waterproof cast for the patient's ankleand foot without the outer surfaces of the tubular elements 10 beingbonded together.

In addition to providing pliable articles for the foregoing type, theflexible, pliable or elastic filaments of the present invention can beinterlaced in any desired manner to provide an elongated strip of fabricsimilar to an elastic bandage which can be applied to a body member orother article by wrapping in overlapping relationship and thereafterexposing to a source of radiant or wave energy to form a rigid supportfor the body member or other article. Effective splints and braces canalso be made by providing a tubular structure which has only a part of acircumference thereof formed of the flexible, pliable or elasticfilament of the present invention with the remainder of thecircumference comprised of an elastic type strip or other suitablematerial.

The filament or tubular article of the present invention can also beused by interlacing, with or without other types of filaments of fibers,so as to provide a woven or non-woven pliable fabric which can be usedfor custom packaging, making industrial shields, shoe liners, automobilebody patch work, fiber glass patch work, sculpture material, angel hairand other decorating material, space-station shields which can be easilyfolded and stowed aboard a space ship and which become structurallystrong after being unfolded and exposed to ultra-violet light, makingdurable press collars or cuffs and other wearing apparel, quick settingsheet-like material which can be draped over a mold and immediatelyhardened, tents and other protective enclosures, and patching materialfor conduits and the like, which becomes structurally strong after beingerected and exposed to sunlight or other source of radiant energy as aresult of the filaments or tubules being rigidified and mechanicallyinterlocked when the incompletely polymerized material within theinterior of the filament is completely polymerized.

The flexible, pliable or elastic elements of the present invention canhave one or more other materials used therewith which impart specialproperties to the elements, such as a coloring agent or a fire retardingsubstance incorporated in the high molecular weight organic compositionor in the polymerizable material or even applied as a coating on thesurface of the flexible element, depending on the energy transmitting orabsorption qualities of the coating material and the nature of theenergy source.

The organic materials which are considered particularly useful forspinning the outer cylindrical sheath portion of a tubular element andthe main body portion of a rod-like element are the high molecularweight organic compositions including but not limited to cellulose,cellulose compounds, and especially the synthetic resins comprisingvinyl, acrylic, olefin, amide, ester, ether, siloxane, urethane, andother known functional groups, including but not limited to the class ofmaterials generally known as elastomers, particularly modern linearpolymers, which are capable of being transformed into flexible, pliableor elastic solids by methods well known in the textile synthetic fiberart. The composition used in each instance must permit passage of thewave energy used to effect polymerization of the core material whilebeing impermeable to the liquid or pliable core material within the spunelement.

The method chosen to produce the filaments or tubules of the presentinvention depends on the nature of the synthetic resin which is used.Melt spinning is appropriate for olefin, amide, ester, and otherpolymers which can be melted and extruded, without deleterious thermaldegradation. Dry spinning, which results in fiber formation byevaporation of solvent from a solution of resin, and wet spinning, whichresults in fiber formation by physical or chemical interaction ofcoagulant with a solution of resin, are appropriate for those resinsthat are stable as solutions but unstable as melts. Combinations ofthese methods are also known and may be used to advantage to maintainthe desired shape of the extruded tubular element, as in the meltspinning of a resin which contains plasticizer or volatile melting-pointdepressant, or in the dry spinning of a resin solution into acoagulation bath. The latter process, which is called "gap spinning", isparticularly useful for resins which may be dry spun or wet spun fromthe same solution.

The polymerizable materials which are capable of being transformed fromthe pliable or liquid incompletely polymerized state to the rigid highlypolymerized state on exposure to radiant or wave energy, include but arenot limited to the polymerizable organic compounds having aphotosensitive initiator admixed therewith, as taught in U.S. Pat. Nos.2,413,973; 3,326,710 (and patents cited therein), 3,613,675, 3,421,501and 3,649,724, and the teaching of these patents are incorporated byreference herein.

It should be understood, however, that the present invention is notlimited to the use of a polymerizable organic material which can bepolymerized by exposure to a source of ultra-violet light or radiantenergy, as other polymerizable organic compositions can be used,including compositions which can be polymerized by ultrasonic energy,such as disclosed in U.S. Pat. No. 3,618,599. Compositions which arepolymerizable by radio frequency waves as taught in U.S. Pat. No.2,871,911 can also be used as the polymerizable material enclosed withinthe elongated flexible element of the present invention. Where it is notobjectionable, polymerization can be effected by a degree of heating.Thus, included among the polymerizable organic compositions which can beused in the present invention are compositions which are polymerizableby exposure to infra-red rays, x-rays, atomic radiation, gamma rays, orother forms of radiant or wave energy. And, in some of the embodimentsof the present invention it is not necessary to use polymerizationinitiator, as where exposure to heat, radiation or other forms of waveenergy is sufficient to cause polymerization in the absence of apolymerization initiator.

It should also be understood that the herein disclosed elongatedflexible, pliable or resilient elements containing a polymerizableorganic material can be combined with one or more other natural orsynthetic fibers, filaments or elongated tubular members where specialproperties are required.

By way of further exemplifying the present invention two extrudedflexible tubular members were formed, one having an outer diameter of0.047 inches and an inner diameter of 0.025 inches and the other havingan outer diameter of 0.077 inches and the inner diameter of 0.058 inchesusing Silastic plastic material (a silicone produced by Dow-Corning ofMidland, Michigan) and having the core portion filled with apolymerizable organic material comprising an isocyanate modifiedbisphenol A glycidyl methacrylate co-monomer blend (No. H3/18/5, Batch73260-manufactured by the L. D. Caulk Company of Milford, Delaware), andcontaining admixed therein as the photosensitizing polymerizationinitiator, a 2 percent solution of benzoin methyl ether in dibutylsebacate. In the co-monomer blend both the main resin and the diluentmonomer which was used to control viscosity were di-functional. One dropof the initiator was used for each gram of the co-monomer. Whereasbefore exposure to ultra-violet radiation each of the above tubularmembers (both the individual elements and when interlaced) containingthe polymerizable co-monomer mixture in the core portion thereof werevery flexible, the individual tubular members and the interlaced tubularmembers exhibited a very rigid structure without any surface bondingbetween the tubular members after a two minute exposure to anultra-violet light source which consisted of a Hanovia No. 679A highpressure Mercury vapor lamp with a total radiated energy of 175.8 wattsover a wavelength region from 220 mm to 1400 mm at a distance of twoinches.

Tubular elements or filaments containing photopolymerizable liquid inthe core thereof in accordance with the present invention were spun bymetering a photopolymerizable liquid into the center of a stream ofmolten polymer immediately before the molten polymer passed through theorifice of a spinneret. The photopolymerizable liquid was prepared byadding 20 drops of a photosensitizing polymerization initiatorconsisting of a 2 percent solution of benzoin methyl ether in dibutylsebacate (H3-53-3, The L. D. Caulk Co.) to 20 g of an isocyanatemodified bisphenol A glycidyl methacrylate co-monomer blend (H4-37-IC,The L. D. Caulk Co.) in an amber bottle, and heating the bottle andcontents at 50° C in an ultrasonic bath for 30 minutes to removeentrapped air. The main resin in the blend was di-functional and thediluent monomer used to control viscosity was tri-functional. The liquidphotopolymerizable mixture, which was stored overnight in the dark atroom temperature before use, was placed in the smaller of two feedcylinders for pumping into the spinning device, and polyethylene resin(DMDA 8925Nt7, Union Carbide Corp.) was placed in the larger cylinderwhich had been heated to 140° C. The molten polyethylene and thephotopolymerizable liquid were pumped through the orifice at rates ofabout 0.7 to 1.3 g/min, and the resulting filaments, which were tubesfilled with the liquid photopolymerizable material, were collected attake-up speeds of 9 to 16 feet/min by a surface-driven winder 4 feetbelow the spinneret. The sample which was collected at 16 feet/min, hada lumen diameter of 0.014 in. and an outer diameter of 0.02. The samplewhich was collected at 9 feet/min. had a lumen diameter of 0.022 inchesand an outer diameter of 0.03 inches.

Portions of each sample were wound around 13-mm glass tubes and exposedto ultraviolet light for ten minutes at a distance of six inches from a200-watt, Hanovia Model S highpressure mercury-vapor lamp. Beforeexposure the samples were soft and very flexible; after exposure bothtest samples were hard and rigid.

The terms "spinning" and "spun" as used in the specification and claimsare intended to denote the all embracing principle of the plasticworking or shaping of material under pressure or tension and in additionto their narrow technical sense comprise also the process of extrusionpressing or drawing, of injection molding and of pressure casting andthe like.

The term "wave energy" as used in the specification and claimsdesignates all forms of energy which are radiated or propagated throughspace by wave or impulse including but not limited to ultraviolet light,x-rays, atomic radiation, gamma rays, sonic waves, radio waves and heatwaves.

We claim:
 1. An article of manufacture comprising a pliable fabrichaving at least one interlaced elongated flexible element, such as asmall diameter filament or tubule, having the body portion of saidelement formed of a high molecular weight organic composition and havingprotectively enclosed and retained entirely within said body portion apolymerizable organic material in a pliable form which when exposed to asource of wave energy which has an intensity effecting polymerization ofsaid polymerizable organic material is transformed to a rigid form andrigidifies the said flexible element and said fabric without having theinterstices of said interlaced elongated flexible element comprisingsaid fabric impregnated with said polymerizable organic material, andsaid fabric characterized by being formable into a desired configurationbefore exposure to said wave energy and while thus formed beingtransformable into a rigid form corresponding to said configuration onexposure to a said source of wave energy.
 2. An article as in claim 1,wherein the said elongated element has at least one longitudinallyextending enclosure formed within said body which retains therein saidpolymerizable organic material.
 3. An article as in claim 2, whereinsaid longitudinally extending enclosure is an axial passage extendinglengthwise of said element.
 4. An article as in claim 1, wherein saidelongated element has said polymerizable organic material distributedalong the length and across the width thereof in a plurality of spacedlongitudinally extending enclosures formed within said body of saidelement.
 5. An article as in claim 1, wherein said fabric has the saidelements interlaced to form a knit fabric.
 6. An article as in claim 1,wherein said fabric has the said elements interlaced to form a wovenfabric.
 7. An article as in claim 1, wherein said fabric has the saidelements interlaced to form a felted fabric.
 8. An article as in claim1, wherein said fabric is interlaced to provide elastic properties andis adapted to yieldably engage a body member when placed in surroundingcontact therewith.
 9. An article as in claim 1, wherein the said body ofthe elongated flexible element is adapted to transmit ultra-violet lighttherethrough, and said source of wave energy is a source of ultra-violetlight.
 10. An article as in claim 1, wherein said elongated flexibleelement is a spun filament having an exterior diameter between about0.001 inches and 0.200 inches.
 11. A pliable fabric which isrigidifiable comprising at least one interlaced elongated small diameterflexible filament having a main body portion formed of a high molecularweight organic composition through which ultra-violet radiation passes,said filament having a photopolymerizable organic composition in apliable form protectively enclosed and retained entirely within its bodyportion throughout the length thereof in at least one longitudinallyextending passage, said photopolymerizable composition beingpolymerizable to a rigid form which effects rigidifying the saidfilament on exposure thereof to ultraviolet radiation without having theinterstices of said interlaced elongated flexible element forming saidfabric impregnated with said polymerizable organic material, and saidfabric characterized by being formable into a select configuration priorto exposure to said ultra-violet radiation and being rigidly held insaid configuration on exposure of said fabric to said ultra-violetradiation.
 12. A pliable fabric as in claim 11, wherein saidphotopolymerizable organic composition contains a photosensitizingpolymerization initiator which is activated on exposure to saidultra-violet radiation.
 13. A pliable fabric as in claim 11, whereinsaid filament is interlaced to form a fabric sleeve structure havingelastic properties which impart stretchability and form-engagingcharacteristics to the fabric sleeve structure.
 14. A pliable fabric asin claim 13, wherein said fabric sleeve has the general configuration ofa portion of a body of a human which enables said sleeve to be mountedon a portion of said body; whereby said sleeve after mounting on saidbody portion forms a rigid support for the said bodily portion onexposure of said sleeve to said ultra-violet radiation.